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.TH MKSTEMP 3C "February 17, 2023"
.SH NAME
mkstemp, mkstemps, mkostemp, mkostemps, mkdtemp \- make a unique file name from a template and open
the file
.SH SYNOPSIS
.nf
#include <stdlib.h>

\fBint\fR \fBmkstemp\fR(\fBchar *\fR\fItemplate\fR);
.fi

.LP
.nf
\fBint\fR \fBmkostemp\fR(\fBchar *\fR\fItemplate\fR, \fBint\fR \fIflags\fR);
.fi

.LP
.nf
\fBint\fR \fBmkstemps\fR(\fBchar *\fR\fItemplate\fR, \fBint\fR \fIslen\fR);
.fi

.LP
.nf
\fBint\fR \fBmkostemps\fR(\fBchar *\fR\fItemplate\fR, \fBint\fR \fIslen\fR, \fBint\fR \fIflags\fR);
.fi

.LP
.nf
\fBchar *\fR\fBmkdtemp\fR(\fBchar *\fR\fItemplate\fR);
.fi

.SH DESCRIPTION
The \fBmkstemp()\fR function replaces the contents of the string pointed to by
\fItemplate\fR by a unique file name, and returns a file descriptor for the
file open for reading and writing. The function thus prevents any possible race
condition between testing whether the file exists and opening it for use. The
string in \fItemplate\fR should look like a file name with six trailing 'X's;
\fBmkstemp()\fR replaces each 'X' with a character from the portable file name
character set. The characters are chosen such that the resulting name does not
duplicate the name of an existing file.
.sp
.LP
The \fBmkstemps()\fR function behaves the same as \fBmkstemp()\fR, except it
permits a suffix to exist in the template. The template should be of the form
/\fBtmp\fR/\fBtmp\fR\fIXXXXXX\fR\fIsuffix\fR. The \fIslen\fR parameter
specifies the length of the suffix string.
.sp
.LP
The \fBmkostemp()\fR and \fBmkostemps\fR are like their \fBmkstemp()\fR and
\fBmkstemps()\fR counterparts except that the \fIflags\fR argument is present
and used to supplement (as a bitwise inclusive-OR) flags to internal
\fBopen()\fR calls.  (e.g. \fBO_SYNC\fR, \fBO_APPEND\fR, and \fBO_CLOEXEC\fR).
.sp
.LP
The \fBmkdtemp()\fR function makes the same replacement to the template as in
\fBmktemp\fR(3C) and creates the template directory using \fBmkdir\fR(2),
passing a \fImode\fR argument of 0700.
.SH RETURN VALUES
Upon successful completion, \fBmkstemp()\fR returns an open file descriptor.
Otherwise \(mi1 is returned if no suitable file could be created.
.SH ERRORS
The \fBmkstemp()\fR, \fBmkstemps()\fR, and \fBmkdtemp()\fR functions can set
\fBerrno\fR to the same values as \fBlstat\fR(2).
.sp
.LP
The \fBmkstemp()\fR and \fBmkstemps()\fR functions can set \fBerrno\fR to the
same values as \fBopen\fR(2).
.sp
.LP
The \fBmkdtemp()\fR function can set \fBerrno\fR to the same values as
\fBmkdir\fR(2).
.SH USAGE
It is possible to run out of letters.
.sp
.LP
The \fBmkstemp()\fR function does not check to determine whether the file name
part of \fItemplate\fR exceeds the maximum allowable file name length.
.sp
.LP
The \fBtmpfile\fR(3C) function is preferred over this function.
.sp
.LP
The \fBmkstemp()\fR function is frequently used to create a temporary file that
will be removed by the application before the application terminates.
.sp
.LP
The \fBmkstemp()\fR function has a transitional interface for 64-bit file
offsets. See \fBlf64\fR(7).
.SH ATTRIBUTES
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
l | l
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	See below.
.TE

.sp
.LP
The \fBmkstemp()\fR function is Standard. The \fBmkstemps()\fR and
\fBmkdtemp()\fR functions are Stable.
.SH SEE ALSO
.BR getpid (2),
.BR lstat (2),
.BR mkdir (2),
.BR open (2),
.BR mktemp (3C),
.BR tmpfile (3C),
.BR attributes (7),
.BR lf64 (7),
.BR standards (7)
